I am in the process of running a water line from my well pump a garden bed about 75 feet away. I will have a separate shut off valve for this water line. At the garden end I will have two hose bibs. This will probably change eventually to drip irrigation or misting systems. Eventually this line will continue to bring water to a green house and other outbuildings that require very little water usage.

Do I need a type of check valve or back-flow preventer at the start of my line ? Or will a back-flow preventer on each hose bib be sufficient. Coming out of the well pump house I will 'T' the line with 1 line going to the house and 1 line going to the garden area.

I live very rural with no local restrictions.

  • 2
    I'm not sure about the codes in your area. If it were me, I'd install a check valve on the line going to the garden, and another check valve on the line going to the house. This prevents the garden line from flowing back to the well, or to the house. It also prevents the house from flowing back to the well.
    – Tester101
    Feb 16, 2015 at 19:38
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    For safety's sake, any irrigation line needs a backflow preventer and vacuum breaker, especially if ever there's a possibility anyone gets the bright idea to do fertilizer injection Feb 17, 2015 at 0:19
  • I ended up putting a check valve on the branch going to the garden bed spigots right after I branch off the main. Its only a few dollars to do and makes sense. Thanks.
    – Web
    Feb 23, 2015 at 15:29

1 Answer 1


You likely need a backflow valve to meet code regulations these days. That said, I don't see any reason to have two of them. Whether it's at the hose bib, or at the well, it's doing the same thing for you.

I suppose one argument for putting it closer to the well is that you block more of the water from back flowing, but if the pipe to the hose is rated for potable, that shouldn't matter.

  • Not sure if it's just my area or IPC, but you need one at each hose bib without mention of an exception. So, it sounds like an "in addition to" situation. If it's required for one on the main pipe at the well, then here you'd need them both. Feb 16, 2015 at 21:15
  • @ChiefTwoPencils I can't speak to the specifics of that, for sure, but I know that was code in places I've been too, but I was under the impression it was because it was the more practical place to put it on older houses (as adding it to the main plumbing line would be a pain). My understanding is that the backflow serves one purpose and that's to separate potable from not-potable water sources. As long as there is a backflow preventer on the 'side' that the hose is on...so that it can never make it back to the potable lines, it should be fine.
    – DA01
    Feb 16, 2015 at 21:22
  • ...which, does make sense as to why they ask you to put it on the spigot, as you really may not readily know where the lines branch in an older house...so putting it on the outside is the 'surest' way to keep the non potable water completely outside of the lines inside the house.
    – DA01
    Feb 16, 2015 at 21:25
  • I ended up putting a check valve on the branch going to the garden bed spigots right after I branch off the main. Its only a few dollars to do. Thanks.
    – Web
    Feb 23, 2015 at 15:28

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